Microminiature zoom lens

Abstract

Abstract PURPOSE:To correct well aberrations with a simple constitution and make a zoom lens small-sized, by arranging the first lens group, consists of >=2 positive lenses and one >=1 negative lenses and has a positive refracting power, and the second lens group, which consists of >=1 positive and negative lenses, at a variable interbal in order from the object side. CONSTITUTION:By arranging the first lens group to have positive, negative, and positive refracting powers, a negative chromatic aberration on the axis, a positive chromatic aberration of magnification, a negative spherical aberration, and a coma aberration generated from positive lenses are corrected by negative lenses, and an astigmatism and a curvature of field are corrected and positive lenses and negative lenses. By the constitution, where the lens surface in the image side of the lens nearest to the object side is a convex positive lens and the lens in the image side is a meniscus negative lens with the convex facing to the image side, of the second lens group consisting of one, at least, positive lens and negative lens, residual aberrations of the first group are cancelled to correct various aberrations well. The air gap between the first group and the second group is changed for zooming, thus making the zoom lens microminiature.

Inventors

• 👤 Kazuo Tanaka
• 👤 Akira Tajima

Bibliographic Details